In this work, we present the results of simulations conducted using the CAMx model for the reconstruction of the organic aerosol in the Po Valley using the SOAP and VBS chemical schemes. With this last scheme, simulations have also been developed with the introduction of new parameterizations for the calculation of emissions of organic compounds with intermediate volatility, and with the revision of primary organic aerosol emissions and the related volatility distributions. The simulations covered the summer quarter from May to July 2013 and the results were validated using the composition of the organic aerosol obtained from the PMF analysis of data from measurement campaigns carried out in San Pietro Capofiume (BO) and Ispra (VA ). With reference to the organic aerosol complex, the comparison with the experimental data highlighted the fact that the transition to the VBS scheme and the introduction of revisions and new parameterizations of the emissions did not have evident effects on the results of the summer simulations, unlike the winter case discussed in previous studies, essentially because the changes introduced concern anthropogenic emissions, in particular from biomass combustion, which in summer are far less significant than in the winter period while, on the contrary, emissions of biogenic origin increase. Furthermore, we cannot exclude the influence of the greater partition of the organic aerosol towards the gaseous phase in the summer period.

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